Page 217 - Trust in ICT 2017

Trust in ICT 3

4) The trust management platform notifies the subjective trust value to WPH. After that, WPH judges
whether User B has enough authorization to get the document.
5) If the subjective trust value exceeds the threshold value,

1-1) WPH sends the document to User B's smartphone.
1-2) Then, the smartphone notifies User B of results.
6) If the subjective trust value is lower than the threshold value,

1-3) WPH notifies that the request was denied.
1-4) Then, the smartphone notifies User B of results.

3.4 Trust matrix

Trust matrix presents trust relationship among actors in this use case.

Table IV.3 – Trust matrix for document sharing service

To Smartphone / Wireless portable Trust Management Platform User
From hard drive
Trusted data collection and
Smartphone / Wireless - aggregation Ownership
portable hard drive
Trusted data process and analysis
Trusted data collection and
Trust Management aggregation
Platform - -
Trusted data process and analysis
User Ownership - -

3.5 Analysis

– Trusted data collection and aggregation
• Social relationship information: This trust property represents whether or not the trustee is
socially cooperative with the trustor. We use the social friendship relationship among device
owners to characterize the cooperativeness.
• CoI information: This trust property represents whether or not the trustor and trustee are in
the same social communities of interest (e.g., co-location, co-work, or parental object
relationship).
– Trusted data process and analysis
• A trust management platform processes and analyses data from other devices to produce useful
information (e.g., subjective trust value) to a user.
– Ownership: This trust property represents whether or not the objects (smartphones) used by the
device owner.

4 Device selection for data transmission

4.1 Description
This use case also focuses on using the social trust when selecting the device for data transmission in multi-
hop D2D (Device-to-Device) environment. Reliable transmission is possible by using social information in the
process of D2D communication. Trust management platform calculates the trust value by using the collected
social data from intermediate entity (e.g., smartphone) of users and then, this trust value will be used to
judge whether that device has enough authorization to send information or not. The social IoT trust also can
be used in the device selection process for the reliable exchange of information. To complement the objective
trust, the subjective trust is required in addition.

209